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Author Topic:   Which animals would populate the earth if the ark was real?
NoNukes
Inactive Member


Message 884 of 991 (709208)
10-22-2013 2:20 PM
Reply to: Message 869 by mindspawn
10-22-2013 6:52 AM


Re: Uniformity assumptions...
Sedimentation would have to be about 50 000 times slower during the Mesozoic to explain fossilisation along the Mississippi. The Mississippi deposits about 200 billion kgs of sediment annually.
Well given that in the right conditions, sedimentation rates can be zero or even negative (erosion), I think your claim that the sedimentation rate cannot vary by a factor of 50,000 is pretty much nonsense.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 869 by mindspawn, posted 10-22-2013 6:52 AM mindspawn has not replied

Replies to this message:
 Message 885 by JonF, posted 10-22-2013 4:34 PM NoNukes has not replied

  
NoNukes
Inactive Member


(3)
Message 886 of 991 (709220)
10-22-2013 5:55 PM
Reply to: Message 875 by mindspawn
10-22-2013 8:48 AM


Re: Uniformity assumptions...
I do not know enough about the process to state the extent of the effect. Or the maths behind it. All I have at this stage is a likely mechanism that would logically effect the rate of decay.
Is the mechanism likely?
Before I put anymore time into this, have you fleshed this out as best as you intend, or should I wait for some more physics.
As I understand things, your theory is that muons have caused fusion which in turn generates a neutron flux that speeds up decay rates?
Why wouldn't those neutrons produce fission instead, particularly when they strike U235 atoms? And in those cases, why don't we see fission products predominate instead of the expected decay daughter products if some significant portion of the U235 atoms absorbed neutrons?
In the case of U235, it is simply not plausible to produce speeded up decay by plunking atoms with neutrons.
When U238 is brought to an excited state by absorbing a neutron, the standard result is that it undergoes two beta decays to produce P-239. Most importantly, though is that it does not produce the expected daugther products that are generated through alpha decay. If this process were going on, we'd know about it.
The other issue is that none of this stuff gets rid of radioactive isotopes in a short amount of time without releasing the energy that is problematic for rapid decay. You still have that issue to solve.
But the fact is that everybody, most likely including you yourself, knows that this proposition of yours is complete nonsense. And if you don't know, you should.
Your claim not to know the extent of the effect when you are relying on it to explain why specific radiometrically determined dates are wrong means you really haven't earned this partial rebuttal anyway. Your still engaged in "see what sticks".
Well this scheme won't stick. It would have left evidence that we don't detect, and likely would require a deadly neutron flux during a period when we both agree that humans walked the earth.
Its more the 0- 600 million ya period that I dispute
This disputed period appears to grow faster than Pinocchio's nose.
ABE:
I just noticed that the claim is that neutrons slowed down decay rates in the past. How is that helpful? Neutron radiation is even more harmful than gamma, alpha and beta radiation. And current rates are still slow. What's up with that?
Surely the claim is not that there was an absence of neutrons in the past. Surely not...
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 875 by mindspawn, posted 10-22-2013 8:48 AM mindspawn has replied

Replies to this message:
 Message 887 by JonF, posted 10-22-2013 6:54 PM NoNukes has seen this message but not replied
 Message 888 by JonF, posted 10-22-2013 8:39 PM NoNukes has not replied
 Message 899 by mindspawn, posted 10-24-2013 7:17 AM NoNukes has replied

  
NoNukes
Inactive Member


(2)
Message 901 of 991 (709286)
10-24-2013 7:54 AM
Reply to: Message 899 by mindspawn
10-24-2013 7:17 AM


This so bad it is disrespectful.
Instead of heavy isotopes steadily decaying, we have a simultaneous process of heavy isotopes being created, or lighter isotopes becoming heavier. This slows down the amount of daughter isotope present in the rock, the parent maintaining its heavy and unstable state.
Uranium shows the same slow rate of decay when we purify it and measure the decay rate in a lab. So apparently this neutron flux must be all around us.
First, this is not what you originally posted. And frankly your scenario is so ridiculous that it is actually insulting that you'd try it here. Among the things I've done in the past is operate a nuclear reactor aboard a submarine. I'm not an amateur on this topic.
Neutrons themselves are deadly radiation. We know that we aren't currently living in a neutron flux because we are not dead. Unlike the case with neutrinos, neutrons are quite detectable. This is one reason why your story is bogus.
Another problem is that the composition of ordinary objects would be constantly changing. An ordinary iron bar would become radioactive over time, and of course would not contain lighter elements to replace the iron nucleii that have become radioactive.
Uranium 235 does not transmute to higher elements when bombarded by neutrons. It undergoes fission roughly into nucleii half roughly original size and releasing lots of energy. This would be quite detectable. The neutron flux would not make it decay or transmute to new elements.
Even water would become more radioactive over time as it absorbed neutrons. What replaces the lightest elements?
ABE:
And please. Stop calling this a "theory"
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 899 by mindspawn, posted 10-24-2013 7:17 AM mindspawn has replied

Replies to this message:
 Message 903 by JonF, posted 10-24-2013 8:41 AM NoNukes has not replied
 Message 916 by mindspawn, posted 10-25-2013 4:42 AM NoNukes has replied

  
NoNukes
Inactive Member


Message 908 of 991 (709319)
10-24-2013 5:23 PM
Reply to: Message 899 by mindspawn
10-24-2013 7:17 AM


Yet another reason to know that this proposition is bogus...
Instead of heavy isotopes steadily decaying, we have a simultaneous process of heavy isotopes being created, or lighter isotopes becoming heavier.
If this were true, then if we were to shield a radioactive element from neutrons, then we should expect that the 'normal' rapid decay of the element would resume, correct?

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 899 by mindspawn, posted 10-24-2013 7:17 AM mindspawn has not replied

  
NoNukes
Inactive Member


Message 909 of 991 (709320)
10-24-2013 5:28 PM
Reply to: Message 902 by JonF
10-24-2013 8:11 AM


Re: Uniformity assumptions...
In stars. The neutron flux, temperature, and pressure on Earth at any time during its existence are nowhere near enough to produce your alleged effect.
Actually, this part of the proposal does work in terrestial conditions. Neutrons, having no charge, easily find their way into the nucleus of atoms.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 902 by JonF, posted 10-24-2013 8:11 AM JonF has replied

Replies to this message:
 Message 918 by JonF, posted 10-25-2013 8:12 AM NoNukes has replied

  
NoNukes
Inactive Member


Message 910 of 991 (709321)
10-24-2013 5:55 PM
Reply to: Message 906 by JonF
10-24-2013 2:07 PM


One more thought: perhaps neutron capture in a sufficiently high flux could "reconstitute" some radioactive parent elements.
I think the idea is that something like U238 gets coverted to U239 before the U238 can alpha decay, and that some poor U237 atom gets converted into a replacement U238 atom. The process must much happen faster than the 'natural' neutron free decay super fast rate of U238 decay that mindspawn also postulates, which means that a huge current neutron flux would be required. He might just as well blame the whole thing on pixie dust.
And of course if I call his 'muon theory' a 'moron theory' then he has an excuse to ignore anything I post.
Do posters familiar with geology find mindspawns statements about the Mississippi just as ridiculous as I find his nuclear chemistry?

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 906 by JonF, posted 10-24-2013 2:07 PM JonF has not replied

Replies to this message:
 Message 911 by jar, posted 10-24-2013 6:25 PM NoNukes has not replied
 Message 912 by petrophysics1, posted 10-24-2013 7:58 PM NoNukes has not replied
 Message 914 by Dr Adequate, posted 10-24-2013 10:10 PM NoNukes has not replied

  
NoNukes
Inactive Member


Message 917 of 991 (709339)
10-25-2013 7:48 AM
Reply to: Message 916 by mindspawn
10-25-2013 4:42 AM


Re: This so bad it is disrespectful.
With a slight neutron background this slows down the decay effect,
Not possible for the flux to be slight. According to you, the neutron flux intervenes by converting atoms to higher isotopes. Thus the flux must affect enough atoms to explain the entire difference between the high decay rates you say used to exist and the current rates.
Also radioactive decay is a random process. The neutron flux must hit affect each atom before it would have decayed to be effective. Every time it strikes the wrong atom we get increased decay rates because the original atom decays anyway. So the neutron flux must greatly exceed the high rate of decay way back when.
So the required neutron flux is not "slight". It must be great. And what happens when the flux is blocked? According to you, any time U235, or any other radioactive material is put behind borated poly shielding it should decay away at extremely high rates. But this does not happen.
And do the non radioactive isotopes in an iron bar get continously heavier over time. Not observed.
Further, isotopes are not uniformly abundant. In fact when we measure the rate of decay of U235 or U238, we take a sample in which the other isotopes have been removed. What explains the slow decay rate in a pure sample containing a single isotope? Your neutron flux would simply remove the single isotope at an increased rate.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 916 by mindspawn, posted 10-25-2013 4:42 AM mindspawn has replied

Replies to this message:
 Message 923 by JonF, posted 10-25-2013 8:51 AM NoNukes has replied
 Message 940 by mindspawn, posted 10-28-2013 7:28 AM NoNukes has replied

  
NoNukes
Inactive Member


Message 919 of 991 (709341)
10-25-2013 8:30 AM
Reply to: Message 915 by mindspawn
10-25-2013 4:11 AM


Re: Uniformity assumptions...
Is there any reason why the effect would not be proportionate?
Yes, in fact there is. A lawyer's rule is to never ask questions that you cannot anticipate the answer for. Here are several reasons not to expect a proportionate effect.
Because the decrease in decay rates depends on a radioactive isotope being replaced by neutron absorption of lighter elements; yet the relative abundance of the lighter elements varies with the element in question. In some cases there are no lighter isotopes elements around at all. Thus your effect cannot be proportionate. Do you understand that the relative abundance of isotopes is something that we can and do measure?
Also some nuclei don't simply become heavier when they absorb a neutron. Instead some other reaction, liked fission or alpha particle emission occurs. U-235 simply cannot behave in the way you require it to, and its slow rate of decay cannot be caused in the way you claim.
Because nuclei vary in their neutron absorption cross section (think of this as the target size the neutron sees) they will be absorb neutrons at different rates. Different isotopes of even the same element have widely different cross sections. So we cannot expect that neutron absorption is proportionate to and in fact nearly matches the decay rate for every single radioactive element used for dating.
Also U-Th dating depends on an equilibrium amount of daughter products, but the daughter products are produced by the decay of the parent atoms. Thus the relationship between the ratio of the amounts of the daughter products and the passage of time is non-linearly related to the decay rates. Multiplying all rates by a constant factor would remove agreement between C-14 dating and say U-Th dating.
And then you still have to explain the agreement between C-14 dating and non-radiometric dating.
Show us the math for how this complex chain of events might work out. Or admit that you really haven't thought this through.
ABE:
Thought of one more argument. The rate of neutron absorption depends on the geometry of a sample. For a large sample, the inner portions of the sample are shielded by the absorption of neutrons by the outer part of the sample. A sample spread out so that it has greater exposed surface area would have a greater rate of neutron absorption even when the external neutron flux is the same as for the large compact sample.
So this neutron flux non-sense cannot explain the independence of decay rates from the geometry of the sample. In fact, it predicts something entirely different. Also neutron absorption rates are strongly affected by temperature while decay rates are essentially independent of temperature.
In short, this is a non-starter proposition.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 915 by mindspawn, posted 10-25-2013 4:11 AM mindspawn has not replied

Replies to this message:
 Message 924 by JonF, posted 10-25-2013 8:56 AM NoNukes has replied

  
NoNukes
Inactive Member


Message 920 of 991 (709342)
10-25-2013 8:35 AM
Reply to: Message 918 by JonF
10-25-2013 8:12 AM


Re: Uniformity assumptions...
Yet I'm sure that elements above iron are only created in supernovae.
Elements above iron and possibly cobalt are all created during supernova. Neutron capture makes heavier isotopes of the same element. As mindspawn pointed out, I was a bit sloppy about that. But then he used that error as an excuse not to explain why a pure sample of U-235 could not possibly follow his scheme.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 918 by JonF, posted 10-25-2013 8:12 AM JonF has not replied

  
NoNukes
Inactive Member


Message 922 of 991 (709344)
10-25-2013 8:39 AM
Reply to: Message 916 by mindspawn
10-25-2013 4:42 AM


Re: This so bad it is disrespectful.
What did I originally post that has changed?
What you originally said was that it is well known that a neutron flux would stop or impede radioactive decay. Now you are postulating a phenomenon that is not "well known" at all, and that actually does not occur at all.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 916 by mindspawn, posted 10-25-2013 4:42 AM mindspawn has not replied

  
NoNukes
Inactive Member


Message 925 of 991 (709347)
10-25-2013 9:10 AM
Reply to: Message 924 by JonF
10-25-2013 8:56 AM


Re: Uniformity assumptions...
But it's not in secular equilibrium with its daughter products and won't be for may thousands of years. We take advantage of that fact.
Thanks. I should have referred to the ratio of elements and the distance of that ratio from the equilibrium value.
No need to apologize for being pedantic when discussing science.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 924 by JonF, posted 10-25-2013 8:56 AM JonF has not replied

  
NoNukes
Inactive Member


Message 927 of 991 (709351)
10-25-2013 9:35 AM
Reply to: Message 923 by JonF
10-25-2013 8:51 AM


Re: This so bad it is disrespectful.
the availability of large quantities of isotopically pure parent nuclides
The neutron flux nonsense requires that the decay rate of an isotopically pure parent be low due to conversion of a U235 to U236 and higher isotopes. Mindspawn has explicitly stated that the conversion is to new isotopes not new elements.
In the case of a pure sample of U235, there are no U234 atoms present, so the sample would simple produce U236. Yet we know that U236 is produced only about 20% of the time a neutron is absorbed. More importantly though, U236 has a very low neutron cross section. We know that U236 is not very much affected by neutrons because it is found in the nuclear reactor waste. U236 does not fission readily. So U236 would be relatively unaffected by the muon produced neutron flux.
So over time, if we ignore the 82 percent of U235 atoms which undergo fission when absorbing neutrons, and we must do that to give mindspawn's nonsense any kind of chance, under a flux we should see a buildup of U236 atoms over time and a depletion of U235 atoms. The rate of conversion must account for all of the radioactive decay of U235 that has been prevented by muon produced neutrons. According to mindspawn, the neutron free decay rate is very high.
It also turns out that U236 has a fairly long decay half life > 120 million years. As the bar gets converted from U235 to U236 at a fairly rapid rate, we should see it's activity increase by a couple orders of magnitude (i.e. by the ratio of U235 to U236 decay constants) over a rapid period.
How rapid? I mean time frames sped up by exactly the same ratio that mindspawn claims that the decay rate was more rapid in the past.
Now how in the world the slow decay rate of U236 could be explained is anyone's guess. Given it's low affinity for neutrons, the process cannot be as suggested by mindspawn. And certainly any reduction in rate cannot be proportionate to that of U238.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 923 by JonF, posted 10-25-2013 8:51 AM JonF has not replied

  
NoNukes
Inactive Member


Message 942 of 991 (709534)
10-28-2013 8:31 AM
Reply to: Message 940 by mindspawn
10-28-2013 7:28 AM


Re: This so bad it is disrespectful.
f you want to make a point about slight or great, we need actual figures. I feel that for an element to have a half-life of a few thousand years is still a slow process that can be affected by the current neutron background.
I note that you provide no numbers in support of your ridiculous proposition but require calculations from me. Why don't you calculate the neutron flux required to delay the radioactive decay of say 100 pounds of U238, and tell me why such a flux would not be detectable when we are in the same room as the U238.
As for borated poly shielding, this neutron background effect would not have much effect on the detection of particle emission during decay, but I do believe the actual production of daughter isotope would greatly increase immediately upon shielding the sample.
Ridiculous. There must be increased emission associated with increased daughter production.
Absent neutrons, where do the daughter products come from if it not from decay of the parent radioactive species? And in the case of U238, many of the daughter products are highly radioactive with half lives measures in seconds or less. So how do the daughter products get produced without decay of the parent species and without producing alpha particles in the case of U235 and U238 once the neutrons are removed from the experiment.
The particle emission would have to increase by exactly the amount of radioactive decay rate slowdown. That is by a factor of millions. That is also the multiplier required for the neutron flux. It must be millions of times greater than the neutron primordial flux.
Further, we can estimate the required neutron flux by multiplying the current radioactivity times the reduction in decay rates.
A good way to measure this would be to arrange two samples of the same consistency of parent/daughter, one shielded and one not.
Your experiment won't work. The effect is not seen.
On nuclear submarines, the entire reactor compartment is lined with neutron shielding so that the crew does not get killed. In order to control the reactor, hafnium rods (neutron absorbers) are inserted inside the uranium core.
There is no increase in radioactivity emission from putting the U235 in the reactor compartment and closing the door. I've actually been in a reactor compartment with the door open and shut, and with radiation monitoring devices, and there is no change at all.
iron is mainly stable, and when pushed into an unstable state (fe59 or fe60) it rapidly decays back to a stable state with days or within a few years.
You are spouting off nonsense without checking easily checkable facts. Fe 60 does not decay rapidly. Fe60 has a half-life of 2.6 millions of years. When Fe60 does decay, it produces Co-60 which is highly radioactive and has a half life of about 5 years. We know what happens to a iron in a neutron because we've seen that any iron rust that manages to enter the high neutron flux region does indeed produce Cobalt 60. Fe59 has a decay rate measured in days.
And short decay rates equals highly radioactive material. If they decay the radiation is detectable. If their decay is somehow prevent by neutron emission, then the neutron flux must be even higher to slow down their decay.
Of course we don't see this happen to iron bars sitting on the kitchen table. They don't become more and more radioactive over time. And certainly not by the amounts needed if there was a neutron flux capable of slowing down U238 decay rates by a factor of one million or so.
ABE:
But more to the point. U235 has a half life of 700 million years, a half life I presume you believe is increased by neutrons. But we know well that the neutrons cause U235 to fission which would greatly increase the rate at which U235 vanishes. So how do neutrons reduce the rate of U235 decay without making the U235 disappear through fission? And wouldn't the fission products contain to decay using their well known decay rates and thus increasing the measured radioactivity from U235? Why isn't this observed
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 940 by mindspawn, posted 10-28-2013 7:28 AM mindspawn has not replied

Replies to this message:
 Message 945 by JonF, posted 10-28-2013 9:33 AM NoNukes has not replied

  
NoNukes
Inactive Member


(1)
Message 949 of 991 (709636)
10-28-2013 9:11 PM
Reply to: Message 937 by mindspawn
10-28-2013 5:52 AM


Re: Uniformity assumptions...
What is slowed is the amount of parent isotope that has decayed into daughter isotope. The rate of transformation from one to the other is slowed down.
Let's explore the implications of this folly using U-238 as the example. U-238's half life is measured at 4.5 * 10^9 years or 1.4110^17 seconds. That half life is determined by detecting the rate of alpha emissions given off by a sample of U-238 as it decays by alpha decay to it's immediate daughter product Th 234. It is this process that you are claiming is slowed by neutrons.
Note however that slowing the process also slows the alpha emission rate. The alpha emission and the production of the daughter product result from the same cause.
Let's consider a 1 gram sample of U-238. Such a sample would contain about 3*10^21 atoms of U-238 (The atomic weight of U238 divided by Avagadros number). The decay of those atoms would be modeled by the following equation:
A = Ao * 1/2^(t/half life) where t is measured in the same units as the half life and Ao would be the initial number of atoms. We can find the decay rate by taking the derivative of the above equation.
dA/dT = 0.693*(Ao/half life)* 1/2^(t/half life).
Now let's consider the rate at the time the 1gram sample was purified and put on our lab bench. t =0.
dA/dT = 0.693 * 2 * 10^21 /1.41 * 10^17 * 1/2^0 = 10^4 decays per second.
That reflects what is actually observed for 1 gram of uranium 238 today.
But according to you, what I have calculated above is a depressed daughter production rate that is caused by a neutron flux. Note that rather than claiming that something caused a high rate back in the past, you claim that the current suppressed rate is caused by the presence of neutrons.
While you have not provided an exact number for the half life of old, you have suggested that it is as low as several thousand years. For convenience let's say 4500 years which also turns out to be 1 million times less than the current decay rate.
Performing the same calculation using a 4500 year half life suggests that the prehistoric rate of daughter production would have been 10^10 decays per second for the same 1 gram of U-238.
Back to the present.
So according to your ridiculous "theory" a neutron flux interacts with atoms of our 1 gram sample to prevent 10^10 - 10^4 decays every second. The difference is just 9.99999*10^9 decays/second daughters prevented. Forgive me if I refer to this difference as just 10^10 per second from now on.
So the neutron flux that strikes our 1 gram sample of U-238 must be on the order of 10^10 neutrons per second. The density of Uranium is about 19 g/cc, so this is the neutron flux that must enter 0.05 cubic centimeters every second.
In fact, 10^10 neutrons per second must be the neutron flux in every single 0.05 cubic centimeter place within our lab that we might choose to move our gram of U-238 or in which we might choose to put additional gram of U-238.
Okay, so what are the real numbers measured in the atmosphere? On the order of 10^6 neutrons per square cm. Completely insufficient for preventing 10^10 daughter products being made in a volume much smaller than a cm3.
I've simplified some things, but I don't believe I've made any simplifications that make things more difficult for you. I ignored the self shielding effect which would make the neutron flux less effective at reaching the inner parts of the sample. I also shrank the 1g sample by 50% when calculating the activity, so the number of decays prevented is too low by a factor of 1.5.
Any how, you wanted calculations. I doubt you'll find what you asked for all that useful, but here it is anyhow.
Edited by NoNukes, : No reason given.
Edited by NoNukes, : No reason given.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

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NoNukes
Inactive Member


Message 950 of 991 (709639)
10-28-2013 9:26 PM
Reply to: Message 937 by mindspawn
10-28-2013 5:52 AM


Re: Uniformity assumptions...
What is slowed is the amount of parent isotope that has decayed into daughter isotope. The rate of transformation from one to the other is slowed down. Our assumption of long timescales is based on currently measured rates of the proportions of parent to daughter isotope over short timeframes.
If we measured the amount of daughter products found in a sample of U238 and found there to be little to no daughter products, what age would we calculate for the sample?
I do not believe the answer is what you think it is.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass

This message is a reply to:
 Message 937 by mindspawn, posted 10-28-2013 5:52 AM mindspawn has not replied

Replies to this message:
 Message 953 by foreveryoung, posted 10-28-2013 10:37 PM NoNukes has not replied

  
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